Outflow and Nutrient Load in Rivers in Sanriku District, Japan
-Considerations Based on Field Observations at the Kesen and Sakari Rivers-
2016 Volume 21 Issue 2 Pages 7-12
Details
2016 Volume 21 Issue 2 Pages 7-12
The Sanriku coastal area suffered serious damage from the Great East Japan Earthquake that occurred on March 11, 2011. Four years have passed since the earthquake, and reconstruction of the aquaculture industry is progressing. In order to achieve sustainable development and promotion, it is necessary to correctly understand the environment of the Sanriku coastline. Sanriku Coast is a type of enclosed coastal sea which is called a rias coast; hence, substances such as nitrogen and phosphorus from rivers flow out and affect water quality. In this study, in order to consider outflow characteristics and nutrient load in two Sanriku rivers, we observed the outflows, water levels and water qualities of each by periodic field observation. As a result, the nutrient loads of the Sanriku rivers were estimated using the HQ curve and LQ equation. Additionally, we estimated the formula of the nutrient load using preceding rainfall. Although there was some variation in reliability due to the adopted period of preceding rainfall, it was successfully demonstrated that it is possible to estimate the substance load through a simple expression.
